Shaft structures of fan

ABSTRACT

A shaft structure having a high service life is disclosed. An outer surface of the shaft is provided with a concave annular area and a plurality of first oil grooves. The first oil grooves extend helically along the outer surface; the fix end has a plurality of toothed portions disposed at interval and along the fixed end radially. A bearing is sleeved on the shaft and has an oil-keeping structure located on the outer surface. Thereby, lubricant can be remained on the surface of the shaft for reducing wear between the shaft and the bearing.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention generally relates to shaft structures and, more particular to, shaft structures of a fan.

Description of Prior Art

A conventional shaft structure of a fan usually provides lubricant between the bearing and the shaft. The lubricant covers the shaft with a distribution of oil film formed by a driving of the shaft so that the shaft will not contact with the bearing in a radial direction during rotation; thus wear and noise can be avoided, and the life of the bearing can be extended. However, when the shaft is stopped from rotating, the lubricant flows out the bearing due to gravity; as a result, the surface of the shaft will be not protected by the oil film. Therefore, when the shaft is rotated again, wear between the shaft and the bearing will be increased, and the shaft can be protected again only after the oil film is reformed after the shaft start rotating. This causes a serious wear on the shaft, and the life of the shaft and the bearing will be reduced.

Moreover, a conventional shaft structure of a fan is assembled between the shaft and the fan blades, and it is implemented by cutting an annular groove at an end of the shaft radially. The annular groove is rolled with knurl; the shaft and the fan blades are coupled by an insert molding process. In this way, plastic material will flow into the annular groove and the knurling for binding. Besides, the center of the fan blades covers an end of the shaft, and the combination of the shaft and the blades of the fan will be completed.

However, the binding structure of the shaft and the blades is only applicable to a metal shaft of the fan. As for a shaft made of ceramic, the above processing is difficult to be applied. Additionally, because the depth of twill configured by the knurl is shallow, the binding force is low and will be easy to fall off. Thus the life of the fan is reduced.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a shaft structure of a fan, wherein lubricant can be remained on a surface of the bearing for reducing wear between the shaft and the bearing; thus the life of the shaft and the bearing will be improved. In order to achieve the object mentioned above, the present invention provides a shaft and a bearing. The shaft is a rod and has an outer surface, a fix end and a free end located opposite to the free end. The outer surface of the shaft is formed with a concave annular area and a plurality of first oil grooves, and the first oil grooves are extend helically along the outer surface. The fix end has a plurality of toothed portions, and the toothed portions are disposed at interval along the fixed end radially. The bearing is a hollow cylinder; the bearing is sleeved on the shaft, and the bearing has an outer surface and an oil-keeping structure located on the outer surface.

Comparing to the prior art, the shaft structure of a fan has a concave annular area and a plurality of first oil grooves, and a plurality of toothed portions provided at the fix end. Besides, an outer surface of the bearing has an oil-keeping structure. Therefore, when lubricant flows into a space between the shaft and the bearing, parts of the lubricant will be remained in the concave annular area of the shaft, the first oil grooves, and the oil-keeping structure of the bearing. Thus, lubricant can be prevented from flowing out the shaft and the bearing, and the surfaces of the shaft and the bearing will be protected by the oil film. Hence the service life of the shaft and the bearing will be improved.

BRIEF DESCRIPTION OF DRAWING

The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself, however, may be best understood by reference to the following detailed description of the invention, which describes a number of exemplary embodiments of the invention, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an application schematic view of the shaft structures of a fan of the present invention.

FIG. 2 is a perspective schematic view of the shaft of the present invention.

FIG. 3 is a perspective schematic view of the bearing of the present invention.

FIG. 4 is an operation schematic view of the shaft structures of a fan of the present invention.

FIG. 5 is another embodiment of the shaft structures of a fan of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In cooperation with attached drawings, the technical contents and detailed description of the invention are described thereinafter according to a number of preferable embodiments, being not used to limit its executing scope. Any equivalent variation and modification made according to appended claims is all covered by the claims claimed by the present invention.

Please refer to FIG. 1, it depicts an application schematic view of the shaft structures of a fan of the present invention. As shown in FIG. 1, the shaft structures of a fan of the present invention is provided for combining with a fan blade assembly 2 and a housing 3. The shaft structures of a fan 1 include a shaft 10 and a bearing 20. One end of the shaft 10 is embedded in the fan blade assembly 2. Moreover, the bearing 20 is sleeved on the shaft 10 and is inserted in the housing 3. Thus, the fan blade assembly 2 can be rotated through the shaft structures of a fan 1.

In the present embodiment, the fan blade assembly 2 includes a hub 4 and a plurality of blades 5 located at a periphery of the hub 4. The hub 4 has an accommodating space 6 and a slot 7 formed therein.

Please further refer to FIG. 2, it depicts a perspective schematic view of the shaft of the present invention. The shaft 10 is a rod, and it has an outer surface 11, a fix end 12 and a free end 13 located oppositely. The outer surface 11 of the shaft 10 is formed with a concave annular area 110 and a plurality of first oil grooves 111. The first oil grooves 111 are extend helically along the outer surface 11. In addition, the fix end 12 has a plurality of toothed portions 121 and is embedded in the fan blade assembly 2 by an insert molding process. The toothed portions 121 are disposed at interval along the fixed end 12 radially. Preferably, the shaft 10 is made of ceramic.

In more detail, the fix end 12 is embedded in the slot 7 of the hub 4 (refer to FIG. 1). Besides, the fix end 12 has an end face 122, and the toothed portions 121 are located on the end face 122. Preferably, the fix end 12 has an annular groove 120, and the annular groove 120 is located in a side of the toothed portions 121 and cut along the fix end 12 radially. Moreover, the concave annular area 110 is a concave surface and located at a middle of the axis 10 approximately. Furthermore, the first oil grooves 111 are located at the concave annular area 110, and the first oil grooves 111 are extended from a middle of the concave annular area 110 to the fix end 12 and the free end 13 separately.

With referring to FIG. 3, it depicts a perspective schematic view of the bearing. The bearing 20 is hollow cylinder. The bearing 20 is sleeved on the shaft 10, and the bearing 20 has an outer surface 21 and an oil-keeping structure 22 located on the outer surface 21.

More specifically, the oil-keeping structure 22 includes a plurality of second oil grooves 221, and the second oil grooves 221 are extend helically along an outer surface 21 of the bearing 20. Preferably, the second oil grooves 221 are located at two sides of the bearing 20 and extend helically in opposite directions.

Please refer to FIG. 4, it depicts an operation schematic view of the shaft structures of a fan of the present invention. The shaft structures of a fan 1 of the present invention are assembled between the fan blade assembly 2 and the housing 3. Moreover, there is lubricant 8 filled between the bearing 10 and the bearing 20 of the shaft structures of a fan 1 of the present invention. When the shaft 10 is driven and rotated, the lubricant 8 provided below the shaft 10 and the bearing 20 will flow upwardly between the shaft 10 and the bearing 20, and an outer periphery of the bearing 2 for lubricating the shaft structures of a fan 1.

As shown in the figure, when the lubricant 8 flows into the shaft 10 and the bearing 20 therebetween, parts of the lubricant 8 will be remained in the concave annular area 110 of the shaft 10 and the first oil grooves 111. Moreover, when the lubricant 8 flows upwardly along the outer periphery of the bearing 20, parts of the lubricant 8 will be remained in the oil-keeping structure 22 (second oil grooves 221). Therefore, the lubricant 8 can be prevented from flowing out of the shaft 10; therefore, the shaft 10 and the surface of the bearing 20 can be protected by the oil film.

Please refer to FIG. 5, it depicts another embodiment of the shaft structures of a fan of the present invention. In the present embodiment, a bearing 20 a is a hollow cylinder. The bearing 20 a has an outer surface 21 a and an oil-keeping structure 22 a located on the outer surface 21 a. The present embodiment differs from the previous embodiment in the deposition of the oil-keeping structure 22 a.

In the present embodiment, the oil-keeping structure 22 a includes a plurality of second oil grooves 221 and an oil slot 222 a. Preferably, the oil slot 222 a is located on an outer periphery of a middle section of the bearing 20 a. Besides, the oil slot 222 a is, but not limited to, a semi-circular slot.

Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and improvements have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and improvements are intended to be embraced within the scope of the invention as defined in the appended claims. 

What is claimed is:
 1. Shaft structures of a fan for combining with a fan blade assembly, including: a shaft being a rod and having an outer surface, a fix end and a free end located opposite to the free end; the outer surface of the shaft being formed with a concave annular area and a plurality of first oil grooves, and the first oil grooves extend helically along the outer surface; the fix end embedded in the fan blade assembly and having a plurality of toothed portions, and the toothed portions disposed at interval along the fixed end radially; and a bearing being a hollow cylinder, the bearing sleeved on the shaft, and the bearing having an outer surface and an oil-keeping structure located on the outer surface.
 2. The shaft structures of a fan according to claim 1, wherein the fan blade assembly includes a hub and a plurality of blades located at a periphery of the hub; the hub has an accommodating space and a slot, and the fix end is embedded in the slot.
 3. The shaft structures of a fan according to claim 1, wherein the fix end has an annular groove, and the annular groove is located at a side of the toothed portions and cut along the fix end radially.
 4. The shaft structures of a fan according to claim 1, wherein the first oil grooves are located at the concave annular area.
 5. The shaft structures of a fan according to claim 1, wherein the first oil grooves are extended from a middle of the concave annular area to the fix end and the free end.
 6. The shaft structures of a fan according to claim 1, wherein the fix end has an end face, and the toothed portions are provided on the end face.
 7. The shaft structures of a fan according to claim 1, wherein the oil-keeping structure includes a plurality of second oil grooves, and the second oil grooves are extend helically along an outer surface of the bearing.
 8. The shaft structures of a fan according to claim 7, wherein the second oil grooves are located at two sides of the bearing and extend helically in opposite directions.
 9. The shaft structures of a fan according to claim 7, wherein the oil-keeping structure further includes an oil slot, and the oil slot is located on an outer periphery of a middle section of the bearing.
 10. The shaft structures of a fan according to claim 9, wherein the oil slot is a semi-circular slot. 